This invention relates to methods and systems for electro-chemical deposition including electroplating of semiconductor substrates.
Electro-chemical deposition, among other processes, is used as a manufacturing technique for the application of films to various structures and surfaces, such as to semiconductor wafers and silicon work pieces or substrates. Such films can include tin silver, nickel, copper or other metal layers. Electro-chemical deposition involves positioning a substrate within a solution that includes metal ions, and then applying an electrical current to cause metal ions from the solution to be deposited on the substrate. Typically, electrical current flows between two electrodes, namely, between a cathode and an anode. When a substrate is used as the cathode, metal can be deposited thereon. A plating solution can include one or more metal ion types, acids, chelating agents, complexing agents, and any of several other types of additives that assist with plating a particular metal. Such additives can help enable adhesion and uniform plating, and reduce film stress, among other benefits. As plating occurs, metal from the plating solution is consumed and thus needs to be replaced to continue electro-chemical deposition operations.